1. Technical Field
The present invention relates to a reservoir for a hydraulic power steering system of a vehicle, and to a method of operating such a system.
2. Description of the Prior Art
A typical hydraulic power steering system for a vehicle, such as an automatic, includes a reservoir containing a body of power steering fluid. The power steering fluid is directed by a pump to a control valve and a hydraulic steering motor, upon rotation of the vehicle steering wheel, to effect steering movement of steerable wheels of the vehicle.
Many automobiles that have power assisted steering also have an automatic transmission. The automatic transmission includes a reservoir containing a body of automatic transmission fluid. The transmission fluid is pumped through the automatic transmission, by an integral pump, to operate the automatic transmission.
The present invention is an apparatus comprising a hydraulic fluid operated automatic transmission for transmitting motive power from an engine of a vehicle to drive wheels of the vehicle. The apparatus also includes a hydraulic fluid power assisted steering gear for effecting steering movement of steerable wheels of the vehicle, the steering gear including a fluid motor. The apparatus further includes a body of hydraulic fluid for operating both of the automatic transmission and the steering gear, and a reservoir for storing a portion of the hydraulic fluid. A transmission fluid pump is connected with the reservoir for pumping hydraulic fluid between the reservoir and the automatic transmission. A power steering pump is connected with the reservoir for pumping hydraulic fluid between the reservoir and the fluid motor. The apparatus also includes a cooler for cooling the hydraulic fluid, one of the power steering pump and the transmission fluid pump being operative to pump hydraulic fluid between the reservoir and the cooler.
The present invention is also a method comprising the steps of:
providing a body of hydraulic fluid;
operating with the hydraulic fluid an automatic transmission to transmit motive power from an engine of a vehicle to drive wheels of the vehicle;
operating with the hydraulic fluid a power assisted steering gear to effect steering movement of steerable wheels of the vehicle, the steering gear including a fluid motor;
storing in a reservoir a portion of the hydraulic fluid that is used for operating both the automatic transmission and the steering gear;
pumping hydraulic fluid between the reservoir and the automatic transmission and the fluid motor; and
pumping hydraulic fluid between the reservoir and a cooler for cooling the hydraulic fluid.